In facilities such as chemical plants, oil refinery plants, and thermal power plants which use large amounts of flammable, explosive, or hazardous materials, it is important to detect corrosion and thinning on pipes and tanks at early stages to prevent serious accidents.
To do so, an abnormality detection system is sometimes employed which includes a temperature distribution measurement apparatus (distributed temperature sensor: DTS) configured to use an optical fiber as a temperature sensor.
This type of abnormality detection system has an optical fiber laid around a pipe or tank, for example, and the optical fiber's end is connected to the temperature distribution measurement apparatus. Then, laser is applied into the optical fiber from the temperature distribution measurement apparatus, and Raman scattered light generated inside the optical fiber is detected with the temperature distribution measurement apparatus to acquire the temperature of the pipe or tank, and the presence of abnormality is determined based on the obtained result.
In facilities such as chemical plants, oil refinery plants, and thermal power plants, a delay in abnormality detection may lead to serious accidents. Thus, a system capable of detecting the occurrence of abnormality at an even earlier stage is desired.
Note that the following patent documents disclose a technique related to the present application.
Patent Document 1: Japanese Laid-open Patent Publication No. 09-18428
Patent Document 1: Japanese Laid-open Patent Publication No. 02-123304
Patent Document 3: International Patent Pamphlet No. WO 2010/125712